With the development of display technologies, an electronic paper technology gets more and more popular in application of e-book reading device due to its unique advantages. The electronic paper technology mainly uses an electrophoretic display technology, which has the following advantages: (i), energy consumption is low, and after the power supply is turned off, electrophoresis can still keep image on the displayer for several days or even several months; (ii), the electronic paper display belongs to a reflection-type display, so that it has good sunlight readability, and the sunlight can be combined with front or side light for display in dark environment; (iii), this technology has a potential of low production costs and does not require strict packaging, and use of solution processing technology such as printing is completely feasible; (iv), the electronic paper can be flexibly shaped, and it can be made on a plastic, metal or glass surface, so that it is a best option for the flexible display technology.
At present, the electronic paper display technology can only display black and white colors, and cannot display color image as the liquid crystal display and organic light-emitting display do. Movement of electrophoretic particles for electronic paper display under different voltages is very complicated, so that it is very difficult for now to make a breakthrough in the color electronic paper display technology.